The present invention relates in general to an air conditioner employing electric power by a solar cell/solar cells as an operation power and more particularly to a method and apparatus for controlling the air conditioner.
A conventional air conditioner using solar cells is disclosed in Japanese Utility Model Publication No. 61-4174/1986. The air conditioner employs the output power of the solar cells as a power supply when the weather is fine and the output power is large, and the air conditioner employs AC power supplied from a commercial AC power supply when the weather is "rainy" or "cloudy" and the output power of the solar cell is small.
The solar cells have not satisfactorily been utilized for the conventional air conditioners since they are not designed for use when output thereof is lower than a predetermined value. The running electric power necessary for the air conditioner may be secured by increasing the area or size of the solar cell assembly when its output is small when it is in rainy or cloudy. The problem, however, is that excessive power may be generated by the increased area of the solar cell when the weather is fine.
Moreover, the optimum operating point of the solar cell which varies with the solar radiation amount is not followed up and the generating efficiency of the solar cell may be deteriorated unless the optimum operating point thereof is followed.
When the air conditioning operation is not needed or when no user is present in an air conditioned room, the solar cell is not utilized, and this has made the utilization factor of the solar cell inferior.